"Pacific Rim" was directed by del Toro and starred Charlie Hunnam, Idris Elba, Rinko Kikuchi, Charlie Day and Robert Kazinsky. Thurday's announcement did not indicate whether the actors will reprise their roles in the sequel.

"Pacific Rim" was set in the 2020s with the Earth using giant "Jaegers" piloted by humans to battle Kaijus -- monsters from an interdimensional portal on the bottom of the Pacific Ocean.

The film, which had a price tag of $190 million, was released last July through Warner Bros. and took in only $101 million in the United States. It performed decently at the international box office with $310 million, led by $114 million in China.

Legendary and Warners ended their co-financing co-producing deal at the end of last year with Legendary signing a long-term pact with Universal.

Del Toro told BuzzFeed on Thursday that original screenwriter Travis Beacham would also be working on the new script.

"The characters I love will return," del Toro told BuzzFeed. "Raleigh, Mako, Newt, Gottlieb and who knows, maybe even Hannibal Chau - but we are taking them into a fresh territory that will display amazing sights and battles. The first film set the stage and now we're ready to have a blast."

In a taped message to fans, del Toro said he has started work on the "Pacific Rim" sequel as he finishes post-production on "Crimson Peak," which Universal opens on Oct. 16, 2015.

"We are happy to be bringing you more Jaegers, more Kaijus, kicking each other's butts," he added.